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J Affect Disord. 2017 Oct 15;221:132-144. doi: 10.1016/j.jad.2017.06.024. Epub 2017 Jun 17.

Decreased functional connectivity and disrupted neural network in the prefrontal cortex of affective disorders: A resting-state fNIRS study.

Author information

1
Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), Guangzhou 510006, PR China. Electronic address: huilin.zhu@m.scnu.edu.cn.
2
Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), Guangzhou 510006, PR China.
3
The Research Center of Psychological Counseling, South China Normal University (SCNU), Guangzhou 510631, PR China.
4
The Department of Clinical Psychology, Guangzhou Brain Hospital (Guangzhou Huiai Hospital, Affiliated Brain Hospital of Guangzhou Medical University), Guangzhou 510170, PR China.
5
Centre for Optical and Electromagnetic Research, South China Academy of Advanced Optoelectronics, South China Normal University (SCNU), Guangzhou 510006, PR China; School of Psychology, South China Normal University (SCNU), Guangzhou 510631, PR China.

Abstract

BACKGROUND:

Affective disorders (AD) have been conceptualized as neural network-level diseases. In this study, we utilized functional near infrared spectroscopy (fNIRS) to investigate the spontaneous hemodynamic activities in the prefrontal cortex (PFC) of the AD patients with or without medications.

METHODS:

42 optical channels were applied to cover the superior frontal gyrus (SFG), middle frontal gyrus (MFG), and inferior frontal gyrus (IFG), which constitute one of the most important affective networks of the brain. We performed resting-state measurements on 28 patients who were diagnosed as having AD and 30 healthy controls (HC). Raw fNIRS data were preprocessed with independent component analysis (ICA) and a band-pass filter to remove artifacts and physiological noise.

RESULTS:

By systematically analyzing the intra-regional, intrahemispheric, and interhemispheric connectivities based on the spontaneous oscillations of Δ[HbO], our results indicated that patients with AD exhibited significantly reduced intra-regional and symmetrically interhemispheric connectivities in the PFC when compared to HC. More specifically, relative to HC, AD patients showed significantly lower locally functional connectivity in the right IFG, and poor long-distance connectivity between bilateral IFG. In addition, AD patients without medication presented more disrupted cortical organizations in the PFC, and the severity of self-reported symptoms of depression was negatively correlated with the strength of intra-regional and symmetrically interhemispheric connectivity in the PFC.

LIMITATIONS:

Regarding the measuring technique, fNIRS has restricted measurement depth and spatial resolution. During the study, the subgroups of AD, such as major depressive disorder, bipolar, comorbidity, or non-comorbidity, dosage of psychotropic drugs, as well as different types of pharmacological responses were not distinguished and systematically compared. Furthermore, due to the limitation of the research design, it was still not very clear how pharmacological treatment affected the resting state cortical organization of the prefrontal lobe, and the degree of the effect in patients with AD.

CONCLUSION:

These results strongly supported that RSFC measured by fNIRS could be a useful and powerful way of delineating the neuropathology of AD.

KEYWORDS:

Affective disorders; Depression; Functional near infrared spectroscopy; Neural networks; Resting-state functional connectivity

PMID:
28645025
DOI:
10.1016/j.jad.2017.06.024
[Indexed for MEDLINE]

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